Given the recent discussion of electronic ignition issues, and concerns on some folks' parts about reliability of either EI or magnetos, I decided to do a little personal research.
I reviewed the NTSB accident database, using the keywords "Magneto failure". Over a 30 year period, 27 accidents had this term. In a significant portion (maybe 1/3) of those a pilot or mechanic theorized that magneto failure had occurred but magneto failure was ruled out (magnetos were functioning correctly), or the cause of the accident was undetermined. In the vast majority of the magneto-failure related accidents since about 2000, failure was ascribed to either non-compliance with required or recommended maintenance (in one case more than 2500 hours since last magneto service/inspection - engine had close to 3000 hours SMOH) or magneto damage due to engine overspeed or backfires. Most of the accidents where magneto failure was a primary cause, with no mention of maintenance or inspection non-compliance, occurred before 2000. Many of these were ag planes (no idea why).
Using the term "magneto" for the search is not practical for this project - most of the references are simply to the pre-flight magneto check (based on a quick sample) and there are too many (>3000) for me to review in detail.
I didn't do any charts or spreadsheets, just scanned the reports and looked at probable causes.
I also tried the term "ignition failure" which returned a total of 6 results: most of these were electronic ignition (one magneto), including Rotax. Given the much smaller number of aircraft flying with electronic ignitions, this is significant but the small "n" makes it hard to draw any meaningful conclusions. None of these accidents were fatal - which makes me suspect that electronic ignition failures in fatal accidents may be very hard to detect, assuming there is more significant damage to engine/airframe/components.
I'm guessing there are a significant number of accidents where magneto failure occurred but damage to the aircraft made determination impossible, however since a majority of engine failure accidents are non-fatal (or forced landing still allows examination of engine even in a fatal accident) I doubt the number is a significant multiple of the known cases. All conjecture on my part, don't rely on my opinions.
Am I being naive or missing the bigger picture?
I reviewed the NTSB accident database, using the keywords "Magneto failure". Over a 30 year period, 27 accidents had this term. In a significant portion (maybe 1/3) of those a pilot or mechanic theorized that magneto failure had occurred but magneto failure was ruled out (magnetos were functioning correctly), or the cause of the accident was undetermined. In the vast majority of the magneto-failure related accidents since about 2000, failure was ascribed to either non-compliance with required or recommended maintenance (in one case more than 2500 hours since last magneto service/inspection - engine had close to 3000 hours SMOH) or magneto damage due to engine overspeed or backfires. Most of the accidents where magneto failure was a primary cause, with no mention of maintenance or inspection non-compliance, occurred before 2000. Many of these were ag planes (no idea why).
Using the term "magneto" for the search is not practical for this project - most of the references are simply to the pre-flight magneto check (based on a quick sample) and there are too many (>3000) for me to review in detail.
I didn't do any charts or spreadsheets, just scanned the reports and looked at probable causes.
I also tried the term "ignition failure" which returned a total of 6 results: most of these were electronic ignition (one magneto), including Rotax. Given the much smaller number of aircraft flying with electronic ignitions, this is significant but the small "n" makes it hard to draw any meaningful conclusions. None of these accidents were fatal - which makes me suspect that electronic ignition failures in fatal accidents may be very hard to detect, assuming there is more significant damage to engine/airframe/components.
I'm guessing there are a significant number of accidents where magneto failure occurred but damage to the aircraft made determination impossible, however since a majority of engine failure accidents are non-fatal (or forced landing still allows examination of engine even in a fatal accident) I doubt the number is a significant multiple of the known cases. All conjecture on my part, don't rely on my opinions.
Am I being naive or missing the bigger picture?
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